Immunogenic compositions against Bacillus anthracis comprising a stabilized protective antigen complex are disclosed. The stabilized complex comprises protective antigen protein and capillary morphogenesis protein-2, with the capillary morphogenesis protein-2 being bound to the protective antigen protein along a binding interface. The stabilized protective antigen complex has increased thermal and structural stability, along with resistance to premature proteolytic degradation. Methods of using the same to induce an immunogenic response in a subject against B. anthracis infection are also disclosed.